need help with triumph id numbers

a friend has inherited a triumph, she sez, its been boarded up in the cellar of her dad's house for at least 25 years, and so far she has only seen the title, which states its a '59 triumph roadster[1/2], the id is TS54600L this sounds like the beginning of an urban legend....... she can't get into the room its boarded up in, and so has not been able to see it......... can anyone help with what this is before i fly out to illinois to figger out how to get it outta there? the horsepower is listed at 184???? thanx, john.